Electroconductive resin composition, sheet, molded product and container

ABSTRACT

An electroconductive resin composition comprising (A) at least one thermoplastic resin selected from the group consisting of a polyphenylene ether type resin, a polystyrene type resin and an ABS type resin, (B) carbon black, and (C) an olefin type resin, said electroconductive resin composition containing from 5 to 50 parts by weight of (B) the carbon black per 100 parts by weight of (A) the thermoplastic resin, and from 1 to 30 parts by weight of (C) the olefin type resin per 100 parts by weight of the total amount of (A) the thermoplastic resin and (B) the carbon black, and said electroconductive resin composition having a surface resistivity of from 10 2  to 10 10  Ω.

This application is a Continuation of application Ser. No. 08/917,606Filed on Aug. 26, 1997, now U.S. Pat. No. 5,876,632, which is aContinuation of Ser. No. 08/834,297, filed Apr. 15, 1997, now U.S. Pat.No. 5,707,699, which is a Continuation of Ser. No. 08/578,480, filedDec. 26, 1995, abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electroconductive resin composition,sheet, molded product and container. More particularly, it relates to anelectroconductive resin composition having an olefin type resinincorporated to an electroconductive rein composition comprising carbonblack and at least one thermoplastic resin selected from the groupconsisting of a polyphenylene ether type resin, a polystyrene type resinand an ABS type resin, so that staining of e.g. IC caused by falling offof e.g. carbon black by abrasion at the time of contact with e.g. IC issubstantially reduced, and an electroconductive sheet, molded productand container made thereof.

2. Discussion of Background

As packaging containers for IC or electronic parts using IC,injection-molded trays, vacuum-formed trays, magazines, embossed carriertapes, etc. have been used. To prevent breakage of IC, etc. due tostatic electricity, these packaging containers have been treated by,e.g., (1) a method of coating an antistatic agent on the surface of thepackaging containers, (2) a method of coating an electroconductivepaint, (3) a method of dispersing an antistatic agent, or (4) a methodof dispersing an electroconductive filler.

Method (1) provides a sufficient antistatic effect immediately after thecoating. However, during the use for an extended period of time, theantistatic agent tends to flow out due to moisture or tends to be lostby abrasion, whereby a constant performance can not be obtained.Further, the surface resistivity is at a level of from 10⁹ to 10¹² Ω,which is not satisfactory for packaging IC, where a high level of anantistatic effect is required.

Method (2) has a drawback that during the preparation, coating tends tobe non-uniform, and the coated paint is likely to fall off by abrasion,whereby the antistatic effect will be lost, thus leading to breakage ofIC, and the lead of IC tends to be stained.

Method (3) has a demerit in that it is necessary to incorporate a largeamount of an antistatic agent, whereby the physical properties of theresin will deteriorate, and the surface resistivity will besubstantially affected by humidity, whereby a constant performance canhardly be obtained.

In method (4), the electroconductive filler may, for example, be finemetal powder, carbon fiber or carbon black. With fine metal powder andcarbon fiber among them, adequate electroconductivity can be obtainedwith a small amount of incorporation, but the moldability will therebysubstantially deteriorate, and it is difficult to uniformly dispersethem. Further, a skin layer composed solely of the resin component islikely to form on the surface of a molded product, and it is difficultto obtain a constant surface resistivity.

Whereas, carbon black can be uniformly dispersed by properly selectingthe kneading conditions, etc., whereby a constant surface resistivitycan easily be obtained. For this reason, carbon black is most commonlyemployed. However, carbon black is required to be incorporated in alarge amount, whereby the fluidity or the moldability tends todeteriorate.

As resins for dispersing carbon black therein, a polyvinyl chloride typeresin, a polypropylene type resin, a polyethylene terephthalate typeresin, a polystyrene type resin and an ABS type resin have been used asresins of general use, and a polyphenylene ether type resin and apolycarbonate resin have been used as heat resistant resins for use at atemperature of 100° C. or higher. Among these resins, a polystyrene typeresin and an ABS type resin as resins of generally use, and apolyphenylene ether type resin as a heat resistant resin, are superiorto other resins in that no substantial deterioration in the fluidity ormoldability is observed even when carbon black is incorporated thereinin a large amount, and they are also excellent from the viewpoint ofcosts. However, compositions obtained by adding a large amount of carbonblack to these resins, have had a drawback that carbon black is likelyto fall off from the surface of their molded products by abrasion.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome such drawbacks andto provide an electroconductive resin composition, sheet, molded productand container, whereby staining of e.g. IC caused by falling off of e.g.carbon black due to the contact and abrasion with e.g. IC issubstantially reduced, by incorporating an olefin type resin to anelectroconductive resin composition comprising carbon black and at leastone thermoplastic resin selected from the group consisting of apolyphenylene ether type resin, a polystyrene type resin and an ABS typeresin.

That is, in a first aspect, the present invention provides anelectroconductive resin composition comprising (A) at least onethermoplastic resin selected from the group consisting of apolyphenylene ether type resin, a polystyrene type resin and an ABS typeresin, (B) carbon black, and (C) an olefin type resin, saidelectroconductive resin composition containing from 5 to 50 parts byweight of (B) the carbon black per 100 parts by weight of (A) thethermoplastic resin, and from 1 to 30 parts by weight of (C) the olefintype resin per 100 parts by weight of the total amount of (A) thethermoplastic resin and (B) the carbon black, and said electroconductiveresin composition having a surface resistivity of from 10² to 10¹⁰ Ω.

In a second aspect, the present invention provides an electroconductiveresin composition comprising (A) at least one thermoplastic resinselected from the group consisting of a polyphenylene ether type resin,a polystyrene type resin and an ABS type resin, (B) carbon black, (C) anolefin type resin, and (D) at least one block copolymer prepared fromstyrene and a conjugated diene, said electroconductive resin compositioncontaining from 5 to 50 parts by weight of (B) the carbon black per 100parts by weight of (A) the thermoplastic resin, and from 1 to 30 partsby weight of (C) the olefin type resin and from 0.2 to 10 parts byweight, in total, of (D) the block copolymer prepared from styrene and aconjugated diene, per 100 parts by weight of the total amount of (A) thethermoplastic resin and (B) the carbon black, and said electroconductiveresin composition having a surface resistivity of from 10² to 10¹⁰ Ω.

In a third aspect, the present invention provides an electroconductiveresin composition comprising (A) at least one thermoplastic resinselected from the group consisting of a polyphenylene ether type resin,a polystyrene type resin and an ABS type resin, (B) carbon black, (C) anolefin type resin, and (E) a resin obtained by hydrogenation of a blockcopolymer prepared from styrene and a conjugated diene and/or a resinobtained by graft polymerization of styrene to a polyolefin, saidelectroconductive resin composition containing from 5 to 50 parts byweight of (B) the carbon black per 100 parts by weight of (A) thethermoplastic resin, and from 1 to 30 parts by weight of (C) the olefintype resin and from 1 to 30 parts by weight, in total, of (E) the resinobtained by hydrogenation of a block copolymer prepared from styrene anda conjugated diene and/or the resin obtained by graft polymerization ofstyrene to a polyolefin, per 100 parts by weight of the total amount of(A) the thermoplastic resin and (B) the carbon black, and saidelectroconductive resin composition having a surface resistivity of from10² to 10¹⁰ Ω.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, the present invention will be described in detail with reference tothe preferred embodiments.

In the present invention, (A) at least one thermoplastic resin selectedfrom the group consisting of a polyphenylene ether type resin, apolystyrene type resin and an ABS type resin, is used. Here, thepolyphenylene ether type resin is a resin comprising a polyphenyleneether resin and a polystyrene type resin as the main components. Thecontent of the polyphenylene ether resin in 100 parts by weight of thetotal amount of the polyphenylene ether resin and the polystyrene typeresin, is preferably from 28 to 86 parts by weight. If the content isless than 28 parts by weight, no adequate dynamical properties as thepolyphenylene ether type resin tend to be obtained, and if it exceeds 86parts by weight, the fluidity tends to be low, whereby molding tends tobe difficult. Such a polyphenylene ether resin may, for example, be ahomopolymer or a copolymer disclosed in U.S. Pat. No. 3,383,435.

The polystyrene type resin to be used in the present invention is theone composed mainly of a common polystyrene resin, an impact-resistantpolystyrene resin, or a mixture thereof.

The ABS type resin is the one composed mainly of a copolymer consistingessentially of three components of acrylonitrile/butadiene/styrene.

(B) carbon black to be used in the present invention may, for example,be furnace black, channel black or acetylene black and preferably theone having a large specific surface area and whereby a high level ofelectroconductivity can be obtained with a small amount of incorporationto the resin. For example, it may be S.C.F. (Super Conductive Furnace),E.C.F. (Electric Conductive Furnace), KETJENBLACK (tradename,manufactured by LION-AKZO) or acetylene black. The amount of carbonblack to be incorporated is an amount whereby the surface resistivity ofthe resulting resin composition, sheet, molded product and containerwill be from 10² to 10¹⁰ Ω. The amount of (B) carbon black is preferablyfrom 5 to 50 parts by weight per 100 parts by weight of (A) thethermoplastic resin. If the amount is less than 5 parts by weight, noadequate electroconductivity can be obtained, and the surfaceresistivity will increase. On the other hand, if it exceeds 50 parts byweight, uniform dispersion into the resin tends to be difficult, themoldability tends to substantially deteriorate, and the properties suchas mechanical strength tend to deteriorate. Further, if the surfaceresistivity exceeds 10¹⁰ Ω, no adequate antistatic effect can beobtained, and if it is less than 10² Ω, the power generating abilitytends to be so good that IC will thereby be destroyed.

(C) the olefin type resin to be used in the present invention may, forexample, be a homopolymer of ethylene or propylene, a copolymer composedmainly of ethylene or propylene, or a blend product thereof.

In the present invention, among these resins, it is preferred to employa polyethylene type resin represented by a low density polyethyleneresin, a high density polyethylene resin or a linear low densitypolyethylene resin, or an ethylene/α-olefin copolymer resin.

Further, in a case where (D) a block copolymer prepared from styrene anda conjugated diene, or (E) a resin obtained by hydrogenation of a blockcopolymer prepared from styrene and a conjugated diene and/or a resinobtained by graft polymerization of styrene to a polyolefin, is used incombination with (C) the olefin type resin, it is particularly preferredto use a polyethylene type resin.

The melt flow index of (C) the olefin type resin to be used in thepresent invention is at least 0.1 g/10 min as measured at 190° C. undera load of 2.16 kg (in accordance with JIS K-7210). If it is less thanthis numerical value, kneading with the polyphenylene ether type resin,the polystyrene type resin or the ABS type resin tends to be difficult,and it will be difficult to obtain a satisfactory composition. Theamount of (C) the olefin type resin is preferably from 1 to 30 parts byweight, more preferably from 3 to 25 parts by weight, per 100 parts byweight of the total amount of (A) the thermoplastic resin and (B) thecarbon black. If the amount is less than 1 part by weight, its effectstend to be inadequate, and if it exceeds 30 parts by weight, it tends tobe difficult to uniformly disperse it into the polyphenylene ether typeresin, the polystyrene type resin or the ABS type resin.

The ethylene/α-olefin copolymer resin to be used in the presentinvention is a resin prepared by copolymerizing ethylene with anα-olefin. The α-olefin copolymerized with ethylene may, for example, bepropylene, butene-1, pentene-1 or hexene-1, specifically "TAFMER P" or"TAFMER A", manufactured by Mitsui Petrochemical Co., Ltd. Theethylene/α-olefin copolymer resin is preferably the one having ahardness of at most 90 as Durometer A type surface hardness stipulatedin JIS K-7215.

In the present invention, (D) the block copolymer prepared from styreneand a conjugated diene is the one wherein the conjugated diene isbutadiene or isoprene. Specifically, it is a block copolymer of styreneand butadiene, or a block copolymer of styrene and isoprene.Specifically, such a block copolymer may, for example, be a branchedstar block copolymer as disclosed in U.S. Pat. No. 3,281,383 or a linearblock copolymer having at least three blocks, as represented by e.g.(S1)-(Bu)-(S2) wherein each of S1 and S2 is a block formed by styrene,and Bu is a block formed by butadiene or isoprene.

Further, when at least two different block copolymers are incorporatedinto the electroconductive resin composition in the present invention,it is preferred that at least one of them is (D1) a star block copolymerhaving a styrene content of from 50 to 90 wt %, and at least one ofother block copolymers is (D2) a star or linear block copolymer having astyrene content of from 10 to 50 wt %. In many cases, this branchedchain star block copolymer contains a straight chain block copolymerfrom the nature of the process for its production, but it is unnecessaryto remove such a straight chain block copolymer, and their mixture maybe employed as it is.

Further, the block copolymer prepared from styrene and a conjugateddiene, to be used in the present invention, may selectively or partiallybe hydrogenated, and a part of double bonds in the blocks made of anisoprene monomer may be hydrogenated.

The amount of (D) the block copolymer prepared from styrene and aconjugated diene is preferably from 0.2 to 10 parts by weight, in total,per 100 parts by weight of the total amount of (A) the thermoplasticresin and (B) the carbon black. If the amount is less than 0.2 part byweight, its effects tend to be inadequate, and if it exceeds 10 parts byweight, it tends to be difficult to disperse it uniformly into thepolyphenylene ether type resin, the polystyrene type resin or the ABStype resin.

In the present invention, as a resin composition comprising (C) theolefin type resin and (D) the block copolymer prepared from styrene anda conjugated diene, it is possible to employ an alloy resin having theblock copolymer previously kneaded together with a styrene type resinand the olefin type resin. As a typical example, the resin compositiondisclosed in Japanese Unexamined Patent Publication No. 311009/1993 maybe employed.

Component (E) to be used in the present invention is a resin obtained byhydrogenation of a block copolymer prepared from styrene and aconjugated diene and/or a resin obtained by graft polymerization ofstyrene to a polyolefin. The conjugated diene of the styrene/conjugateddiene block copolymer to be used for the preparation of the resinobtained by hydrogenation of a block copolymer prepared from styrene anda conjugated diene, is preferably butadiene or isoprene, and the styrenecontent in the styrene/conjugated diene block copolymer is notparticularly limited, but is usually from 10 to 80 wt %, preferably from10 to 50 wt %. On the other hand, the polyolefin used for the resinobtained by graft polymerization of styrene to a polyolefin, ispreferably polyethylene, polypropylene or an ethylene/vinyl acetatecopolymer.

The amount of (E) a resin obtained by hydrogenation of a block copolymerprepared from styrene and a conjugated diene and/or a resin obtained bygraft polymerization of styrene to a polyolefin, is preferably from 1 to30 parts by weight, in total, per 100 parts by weight of the totalamount of (A) the thermoplastic resin and (B) the carbon black. If theamount is less than 1 part by weight, its effects tend to be inadequate,and if it exceeds 30 parts by weight, it tends to be difficult touniformly disperse it in the polyphenylene ether type resin, thepolystyrene type resin or the ABS type resin.

In order for the electroconductive resin composition of the presentinvention to maintain the adequate moldability, when carbon black isincorporated so that the surface resistivity would be from 10² to 10¹⁰Ω, the melt flow index (as measured in accordance with JIS K-7210) ispreferably at least 0.1 g/10 min, as measured at 230° C. under a load of10 kg in the case of the polyphenylene ether type resin, at 200° C.under a load of 5 kg in the case of the polystyrene type resin, and at220° C. under a load of 10 kg in the case of the ABS type resin.

Further, to the electroconductive resin composition of the presentinvention, it is possible to incorporate various additives such as alubricant, a plasticizer, a processing assistant and a reinforcingagent, and other resin components, to improve the flow properties of thecomposition and the dynamic properties of the molded product.

To prepare the electroconductive resin composition of the presentinvention, it is possible to carry out kneading and pelletizing by meansof conventional methods using e.g. a Banbury mixer, an extruder, etc.With respect to kneading of the electroconductive resin composition, thestarting materials may be kneaded all at once. Otherwise, kneading maybe stepwisely conducted by separately kneading, for example, a mixtureof the styrene type resin and the carbon black, a mixture of the styrenetype resin and the olefin type resin, and a mixture of the styrene typeresin and the block copolymer, and finally putting such kneaded productstogether, followed by kneading.

The thickness of the entire sheet of the present invention is preferablyfrom 0.1 to 3.0 mm. If the thickness is less than 0.1 mm, the strengthof the packaging container obtainable by molding the sheet tends to beinadequate, and if it exceeds 3.0 mm, forming such as pressure forming,vacuum forming or thermoforming tends to be difficult.

Electroconductive plastic containers of the present invention aresuitable for packaging IC. Specifically, they may, for example, bevacuum formed trays, magazines or embossed carrier tapes for packagingIC and vacuum formed trays for packaging electronic parts or electronicequipments using IC, and they may be obtained by processing theabove-mentioned electroconductive plastic sheet by a conventionalsheet-forming method such as pressure forming, vacuum forming orthermoforming.

Further, the injection molded electroconductive plastic product of thepresent invention can readily be obtained by subjecting theabove-mentioned electroconductive resin composition to a conventionalinjection molding method.

Now, the present invention will be described in further detail withreference to Examples. However, it should be understood that the presentinvention is by no means restricted by such specific Examples.

EXAMPLES 1 to 12

Using the materials as identified in Table 1, the respective materialswere weighed in the compositional ratios as identified in Table 2,uniformly mixed by high speed mixing, then kneaded by means of a φ45 mmvented twin-screw extruder and pelletized by a strand cut method toobtain a conductive resin composition. The obtained resin compositionwas extruded by means of a φ65 mm extruder (L/D=28) and a T-die having awidth of 500 mm to obtain a sheet having an entire thickness of 300 μm.

Further, the obtained sheet was subjected to vacuum forming to obtainvacuum-formed trays and embossed carrier tapes for packaging IC of QFP14 mm×20 mm/64 pin.

On the other hand, the obtained conductive resin composition was moldedby an injection molding machine (100 t) to obtain a plate-like moldedproduct having a thickness 1 mm and a size of 120 mm×120 mm and a moldedproduct having a shape of a test sample for tensile properties.

The evaluation results of the composition, sheet, vacuum-formed tray,embossed carrier tape and injection-molded sample are shown in Table 4.In each Example, no falling of carbon black was observed.

COMPARATIVE EXAMPLES 1 to 6

In the same manner as in the Examples, using the materials as identifiedin Table 1, the respective materials were weighed in the compositionalratios as identified in Table 3, uniformly mixed by high speed mixing,then kneaded by means of a φ45 mm vented twin-screw extruder andpelletized by a strand cut method to obtain an electroconductive resincomposition. Then, the obtained resin composition was extruded by meansof a φ65 mm extruder (L/D=28) and a T-die with a width of 500 mm toobtain a sheet having an entire thickness of 300 μm.

Further, the obtained sheet was subjected to vacuum forming to obtainvacuum-formed trays and embossed carrier tapes for packaging IC of QFP14 mm×20 mm/64 pin.

On the other hand, the obtained electroconductive resin composition wasmolded by an injection molding machine (100 t) to obtain a plate-likemolded product having a thickness of 1 mm and a size of 120 mm×120 mmand a molded product having a shape of a test sample for tensileproperties. The evaluation results of the composition, sheet,vacuum-formed tray, embossed carrier tape and injection-molded sampleare shown in Table 4. In each Comparative Example, falling of carbonblack was observed.

The respective evaluations were carried out by the following methods.

(1) Surface Resistivity

Using a Rolestar surface resistivity meter (manufactured by MitsubishiPetrochemical Co., Ltd.), the electrode distance was set to be 10 mm,and with respect to the sheet sample and the injection molded product,the resistivity was measured at optional ten points on the surfacethereof, and with respect to the vacuum-formed tray and the embossedcarrier tape, the resistivity was measured at 10 points at the center ofthe inner bottom surface of the pocket portion thereof, whereupon therespective logarithmic mean values were taken as the surfaceresistivity.

(2) Strength at Break and Tensile Modulus

In accordance with JIS K-7113, with respect to the sheet sample, a No. 2test specimen was measured, and with respect to the injection moldedproduct, a No. 1 test specimen was measured, at a tensile speed of 10mm/min.

(3) Presence or Absence of Falling of Carbon Black

With respect to the sheet sample and the injection molded product, IC ofQFP 14 mm×20 mm/64 pin was pressed against the surface under a load of100 g, and it was reciprocated 100 times at a stroke of 15 mm, whereuponthe lead portion of IC was inspected by a microscope.

With respect to the vacuum-formed tray and the embossed carrier tape,the same IC was mounted in the pocket portion and vibrated at a speed of400 reciprocations per minute with a stroke of 30 mm in a planedirection for 200,000 times, whereupon the lead portion of IC wasinspected by a microscope. The evaluation was made based on whether ornot black deposition of carbon black or the like on the lead portion wasobserved.

(4) MFI

With respect to the electroconductive resin compositions of therespective Examples and Comparative Examples, MFI was measured inaccordance with JIS 7210.

                                      TABLE 1    __________________________________________________________________________    Materials    Name            Grade       Manufacturers    __________________________________________________________________________    Polyphenylene ether type resin                    NORYL-731J  GE plastic    Impact-resistant polystyrene resin                    HI-E4       Denki Kagaku Kogyo K.K.    Transparent polystyrene resin                    HRM-5       Denki Kagaku Kogyo K.K.    ABS resin       SE-10       Denki Kagaku Kogyo K.K.    Carbon black    Granular DENKA BLACK                                Denki Kagaku Kogyo K.K.    Carbon black    KETJENBLACK LION-AKZO    Carbon black    VULCAN-XC-72                                Cabolac    Linear low density polyethylene resin                    ULTZEX 1520L                                Mitsui Petrochemical Co.    Linear low density polyethylene resin                    ULTZEX 2022L                                Mitsui Petrochemical Co.    Linear low density polyethylene resin                    ULTZEX 3520L                                Mitsui Petrochemical Co.    High density polyethylene resin                    HI-ZEX 5000S                                Mitsui Petrochemical Co.    Low density polyethylene resin                    MIRASON 102 Mitsui Petrochemical Co.    Low density polyethylene resin                    MIRASON 12  Mitsui Petrochemical Co.    Ethylene-ethyl acrylate copolymer                    NUC-6169    Nippon Unicar    resin    Ethylene/α-olefin copolymer resin                    TAFMER P-0280                                Mitsui Petrochemical Co.    Ethylene/α-olefin copolymer resin                    TAFMER A-4085                                Mitsui Petrochemical Co.    Linear styrene/butadiene block                    STR-1602    Denki Kagaku Kogyo K.K.    copolymer resin    Star styrene/butadiene block                    STYROLUX-684D                                BASF    copolymer resin    Star styrene/butadiene block                    K-RESIN KR03                                Philips    copolymer resin    Star styrene/butadiene block                    STYROBLEND KR-2776                                BASF    copolymer-polystyrene resin    containing olefin type resin    Hydrogenated styrene/diene block                    TUFTEC-H-1051                                Asahi Kasei K.K.    copolymer resin    Ethylene/styrene graft copolymer                    VMX-AN-50F  Mitsubishi Chemical    resin                       Corporation    __________________________________________________________________________

                                      TABLE 2    __________________________________________________________________________           Materials   Examples           Grade       1  2  3  4  5  6  7 8 9 10 11 12    __________________________________________________________________________    Compositional           NORYL-731J  100                          100                             100                                100    ratio  HI-E4                   100                                      100                                         70                                           70                                             70           HRM-5                         30                                           30                                             30           SE-10                               100                                                  100                                                     100           Granular DENKA BLACK                       26    26       25          30           KETJENBLACK    12       12          12           VULCAN-XC-72         24       24                                           24                                             24      24           ULTZEX 1520L         6           ULTZEX 2022L               3           ULTZEX 3520L                        15           HI-ZEX 5000S   20       6                 15    Compositional           MIRASON 102 20    ratio  MIRASON 12                    10           NUC-6169          4  4  8           TAFMER P-0280     20           TAFMER A-4085                   30     10           STR-1602             1  0.4               3           STYROLUX-684D        2  0.4           K-RESIN KR03                              3           STYROBLEND KR-2776                40           TUFTEC-H-1051              15           VMX-AN-50F     5    __________________________________________________________________________

                                      TABLE 3    __________________________________________________________________________              Materials   Comparative Examples              Grade       1  2  3  4 5 6    __________________________________________________________________________    Compositional ratio              NORYL-731J  100              HI-E4          100                                100                                   70                                     70              HRM-5                30                                     30              SE-10                    100              Granular DENKA BLACK                          26              KETJENBLACK    12 12     12              VULCAN-XC-72         24                                     22              ULTZEX 1520L              ULTZEX 2022L           3              ULTZEX 3520L              HI-ZEX 5000S    Compositional ratio              MIRASON 102          45              MIRASON 12              NUC-6169              TAFMER P-0280          45              TAFMER A-4085              STR-1602          0.4              STYROLUX-684D     0.4              K-RESIN KR03              STYROBLEND KR-2776              TUFTEC-H-1051              VMX-AN-50F    __________________________________________________________________________

                                      TABLE 4    __________________________________________________________________________                Sheet sample        Vacuum-formed tray         Composition                Surface                     Strength                          Tensile                                Falling                                    Surface                                         Falling         MFI    resistivity                     at break                          modulus                                off of                                    resistivity                                         off of         (g/10 min)                (Ω)                     (kgf/mm.sup.2)                          (kfg/mm.sup.2)                                carbon                                    (Ω)                                         carbon    __________________________________________________________________________    Examples    1    2.5    1.3 × 10.sup.5                     4.1  149   Nil 2.0 × 10.sup.5                                         Nil    2    2.8    2.6 × 10.sup.4                     4.3  145   Nil 3.0 × 10.sup.4                                         Nil    3    3.0    1.3 × 10.sup.5                     4.1  149   Nil 2.6 × 10.sup.5                                         Nil    4    2.9    2.3 × 10.sup.5                     4.3  149   Nil 4.5 × 10.sup.5                                         Nil    5    3.0    8.0 × 10.sup.4                     1.9  130   Nil 1.2 × 10.sup.5                                         Nil    6    3.1    5.2 × 10.sup.4                     2.0  130   Nil 6.8 × 10.sup.4                                         Nil    7    3.3    4.8 × 10.sup.4                     2.5  125   Nil 1.0 × 10.sup.5                                         Nil    8    3.1    5.2 × 10.sup.4                     2.2  128   Nil 7.3 × 10.sup.4                                         Nil    9    3.0    1.1 × 10.sup.5                     2.1  130   Nil 9.1 × 10.sup.4                                         Nil    10   2.8    7.4 × 10.sup.5                     2.7  133   Nil 9.2 × 10.sup.5                                         Nil    11   2.8    7.0 × 10.sup.4                     2.7  133   Nil 4.3 × 10.sup.4                                         Nil    12   2.4    9.7 × 10.sup.4                     2.3  134   Nil 2.1 × 10.sup.6                                         Nil    __________________________________________________________________________    Embossed carrier tape                      Injection-molded sample         Surface      Surface                            Strength                                  Tensile         resistivity               Falling                      resistivity                            at break                                  modulus                                        Falling         (Ω)               off of carbon                      (Ω)                            (kgf/mm.sup.2)                                  (kgf/mm.sup.2)                                        off of carbon    __________________________________________________________________________    Examples    1    1.9 × 10.sup.5               Nil    2.3 × 10.sup.6                            4.3   150   Nil    2    3.2 × 10.sup.4               Nil    4.2 × 10.sup.5                            4.4   149   Nil    3    3.2 × 10.sup.5               Nil    2.3 × 10.sup.6                            4.3   150   Nil    4    4.0 × 10.sup.5               Nil    9.7 × 10.sup.5                            4.3   149   Nil    5    5.1 × 10.sup.5               Nil    8.0 × 10.sup.4                            1.9   130   Nil    6    6.5 × 10.sup.4               Nil    9.0 × 10.sup.4                            1.8   129   Nil    7    2.1 × 10.sup.5               Nil    7.3 × 10.sup.4                            2.3   125   Nil    8    6.9 × 10.sup.4               Nil    9.0 × 10.sup.4                            2.3   129   Nil    9    8.9 × 10.sup.4               Nil    2.4 × 10.sup.5                            2.1   130   Nil    10   8.8 × 10.sup.5               Nil    1.1 × 10.sup.5                            2.9   132   Nil    11   9.7 × 10.sup.4               Nil    8.7 × 10.sup.4                            2.9   132   Nil    12   2.9 × 10.sup.5               Nil    1.5 × 10.sup.5                            2.3   134   Nil    __________________________________________________________________________                Sheet sample        Vacuum-formed tray          Composition                Surface                     Strength                          Tensile                               Falling                                    Surface                                         Falling          MFI   resistivity                     at break                          modulus                               off of                                    resistivity                                         off of          (g/10 min)                (Ω)                     (kgf/mm.sup.2)                          (kgf/mm.sup.2)                               carbon                                    (Ω)                                         carbon    __________________________________________________________________________    Comparative    Example    1     1.9   7.6 × 10.sup.4                     4.2  151  Observed                                    8.6 × 10.sup.4                                         Observed    2     2.2   1.7 × 10.sup.4                     2.2  130  Observed                                    4.7 × 10.sup.4                                         Observed    3     2.9   3.0 × 10.sup.4                     2.1  132  Observed                                    4.0 × 10.sup.4                                         Observed    4     5.1   5.9 × 10.sup.4                     1.9  113  Observed                                    8.0 × 10.sup.4                                         Observed    5     4.0   7.8 × 10.sup.4                     1.9  123  Observed                                    8.2 × 10.sup.4                                         Observed    6     3.0   5.3 × 10.sup.5                     2.6  134  Observed                                    6.9 × 10.sup.5                                         Observed    __________________________________________________________________________           Embossed carrier tape                       Injection-molded sample           Surface     Surface                            Strength                                  Tensile           resistivity                Falling                       resistivity                            at break                                  modulus                                       Falling           (Ω)                off of carbon                       (Ω)                            (kgf/mm.sup.2)                                  (kgf/mm.sup.2)                                       off of carbon    __________________________________________________________________________    Comparative    Examples    1      8.0 × 10.sup.4                Observed                       8.9 × 10.sup.5                            4.3   150  Observed    2      5.1 × 10.sup.4                Observed                       1.9 × 10.sup.5                            2.3   132  Observed    3      4.9 × 10.sup.4                Observed                       6.7 × 10.sup.5                            2.0   133  Observed    4      8.5 × 10.sup.4                Observed                       5.9 × 10.sup.5                            1.9   110  Observed    5      9.0 × 10.sup.4                Observed                       5.7 × 10.sup.5                            1.9   123  Observed    6      6.5 × 10.sup.5                Observed                       1.6 × 10.sup.5                            2.7   133  Observed    __________________________________________________________________________

As described in the foregoing, by incorporating an olefin type resin toan electroconductive resin composition comprising carbon black and atleast one thermoplastic resin selected from the group consisting of apolyphenylene ether type resin, a polystyrene type resin and an ABS typeresin, it is possible to obtain an electroconductive resin composition,sheet, molded product and container, whereby staining of e.g. IC causedby falling off of carbon black due to abrasion at the time of contactwith e.g. IC can be substantially reduced.

What is claimed is:
 1. A packaged product comprising (1) an integratedcircuit or an electronic component comprising an integrated circuit, ina (2) container, wherein the container is made of an electroconductiveresin composition consisting essentially of(A) a polystyrene resin, highimpact polystyrene resin, or a mixture of thereof, (B) 5 to 50 parts byweight of carbon black per 100 parts by weight of (A); and (C) 1 to 30parts by weight of an olefin resin per 100 parts by weight of (A);wherein said electroconductive resin composition has a surfaceresistivity of from 10² to 10¹⁰ Ω.
 2. A packaged product comprising (1)an integrated circuit or an electronic component comprising anintegrated circuit, in a (2) container, wherein the container is made ofan electroconductive resin composition consisting essentially of(A) apolystyrene resin, high impact polystyrene resin, or a mixture ofthereof, (B) carbon black, (C) an olefin resin, and (D) at least oneblock copolymer prepared from styrene and a conjugated diene, saidelectroconductive resin composition containing from 5 to 50 parts byweight of (B) the carbon black per 100 parts by weight of (A), and from1 to 30 parts by weight of (C) the olefin resin and from 0.2 to 10 partsby weight, of (D) the block copolymer prepared from styrene and aconjugated diene, per 100 parts by weight of the total amounts of (A)and (B) the carbon black, and wherein said electroconductive resincomposition has a surface resistivity of from 10² to 10¹⁰ Ω.
 3. Apackaged product comprising (1) an integrated circuit or an electroniccomponent comprising an integrated circuit, in a (2) container, whereinthe container is made of an electroconductive resin composition,consisting essentially of(A) a polystyrene resin, high impactpolystyrene resin, or a mixture of thereof, (B) carbon black, (C) anolefin resin, and (E) a resin obtained by hydrogenation of a blockcopolymer prepared from styrene and a conjugated diene and/or a resinobtained by graft polymerization of styrene to a polyolefin, saidelectroconductive resin composition containing from 5 to 50 parts byweight of (B) the carbon black per 100 parts by weight of (A), and from1 to 30 parts by weight of (C) the olefin resin and from 1 to 30 partsby weight, of (E) the resin obtained by hydrogenation of a blockcopolymerization prepared from styrene and a conjugated diene and/or theresin obtained by graft polymerization of styrene to a polyolefin, per100 parts by weight of the total amount of (A) and (B) the carbon black,and wherein said electroconductive resin composition has a surfaceresistivity of from 10² to 10¹⁰ Ω.
 4. A packaged product comprising (1)an integrated circuit or an electronic component comprising anintegrated circuit, in a (2) container, wherein the container is made ofan electroconductive resin composition consisting essentially of(A) apolystyrene resin, a high impact polystyrene resin, or a mixturethereof, (B) carbon black, (C) an olefin resin, and (D) at least twoblock copolymers prepared from styrene and a conjugated diene,wherein atleast one of them is (D1) a star block copolymer having a styrenecontent of from 50 to 90 wt %, and at least one of other blockcopolymers is (D2) a star of linear block copolymer having a styrenecontent of from 10 to 50 wt %, said electroconductive resin compositioncontaining from 5 to 50 parts by weight of (B) the carbon black per 100parts by weight of (A), and from 1 to 30 parts by weight of (C) theolefin resin and from 0.2 to 10 parts by weight, of (D) the blockcopolymers prepared from styrene and a conjugated diene, per 100 partsby weight of the total amounts of (A) and (B) the carbon black, andwherein said electroconductive resin composition has a surfaceresistivity of from 10² to 10¹⁰ Ω.
 5. The packaged product according toclaim 1, wherein (C) the olefin resin is a polyethylene resin.
 6. Thepackaged product according to claim 2, wherein (C) the olefin resin is apolyethylene resin.
 7. The packaged product according to claim 3,wherein (C) the olefin resin is a polyethylene resin.
 8. The packagedproduct according to claim 4, wherein (C) the olefin resin is apolyethylene resin.